%0 Journal Article
%4 sid.inpe.br/marciana/2003/06.10.15.56
%2 sid.inpe.br/marciana/2003/06.10.15.56.19
%@issn 0004-637X
%@issn 1538-4357
%T High-Energy X-Ray Timing Experiment detections of hard X-ray tails in Scorpius X-1
%D 2001
%8 Feb.
%9 journal article
%A D'Amico, Flávio,
%A Heindl, W. A.,
%A Rothschild, R. E.,
%A Gruber, D. E,
%@affiliation Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, USA
%@affiliation Inst Nacl Pesquisas Espaciais, Divisão de Astrofísica
%@electronicmailaddress fdamico@ucsd.edu
%@electronicmailaddress wheindl@ucsd.edu
%@electronicmailaddress rrothschild@ucsd.edu
%@electronicmailaddress dgruber@ucsd.edu
%B Astrophysical Journal
%V 547
%N 2 Part 2
%P L147-L150
%K Astrofísica, binaries : general, stars : individual (Scorpius X 1), stars : neutron, X-rays : stars, performance, explorer, spectrum.
%X We report the detection of a nonthermal hard X-ray component from Sco X-1 based on the analysis of 20-220 keV spectra obtained with the High-Energy X-Ray Timing Experiment on board the Rossi X-Ray Timing Explorer satellite. We find that the addition of a power-law component to a thermal bremsstrahlung model is required to achieve a good fit in five of 16 observations analyzed. Using Proportional Counter Array data, we were able to track the movement of the source along the Z diagram, and we found that the presence of the hard X-ray tail is not confined to a specific Z position. However, we do observe an indication that the power-law index hardens with increasing M, as indicated from the position on the Z diagram. We find that the derived nonthermal luminosities are similar to 10% of that derived for the brightest of the atoll sources.
%@language en
%3 High-energy x-ray timing experiment detections of hard x-ray tails in scorpius x-1.pdf